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 * Copyright (c) 2024, 2024, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
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package com.oracle.svm.core.posix;

import static com.oracle.svm.core.Uninterruptible.CALLED_FROM_UNINTERRUPTIBLE_CODE;

import org.graalvm.nativeimage.IsolateThread;
import org.graalvm.nativeimage.Platform;
import org.graalvm.nativeimage.Platforms;

import com.oracle.svm.core.Uninterruptible;
import com.oracle.svm.core.graal.stackvalue.UnsafeStackValue;
import com.oracle.svm.core.posix.headers.Time;
import com.oracle.svm.core.traits.BuiltinTraits.AllAccess;
import com.oracle.svm.core.traits.BuiltinTraits.SingleLayer;
import com.oracle.svm.core.traits.SingletonLayeredInstallationKind.InitialLayerOnly;
import com.oracle.svm.core.traits.SingletonTraits;
import com.oracle.svm.core.util.TimeUtils;

import jdk.graal.compiler.word.Word;

/**
 * Support for POSIX global timer (see {@link PosixSubstrateSigprofHandler}).
 */
@SingletonTraits(access = AllAccess.class, layeredCallbacks = SingleLayer.class, layeredInstallationKind = InitialLayerOnly.class)
public final class PosixSubstrateGlobalSigprofHandler extends PosixSubstrateSigprofHandler {

    @Platforms(Platform.HOSTED_ONLY.class)
    public PosixSubstrateGlobalSigprofHandler() {
    }

    @Override
    protected void updateInterval() {
        updateInterval(TimeUtils.millisToMicros(newIntervalMillis));
    }

    private static void updateInterval(long us) {
        Time.itimerval newValue = UnsafeStackValue.get(Time.itimerval.class);
        newValue.it_value().set_tv_sec(us / TimeUtils.microsPerSecond);
        newValue.it_value().set_tv_usec(us % TimeUtils.microsPerSecond);
        newValue.it_interval().set_tv_sec(us / TimeUtils.microsPerSecond);
        newValue.it_interval().set_tv_usec(us % TimeUtils.microsPerSecond);

        int status = Time.NoTransitions.setitimer(Time.TimerTypeEnum.ITIMER_PROF, newValue, Word.nullPointer());
        PosixUtils.checkStatusIs0(status, "setitimer(which, newValue, oldValue): wrong arguments.");
    }

    @Override
    protected void installSignalHandler() {
        super.installSignalHandler();
        updateInterval();
    }

    @Override
    protected void uninstallSignalHandler() {
        /* Disable sampling. */
        updateInterval(0);
    }

    @Override
    @Uninterruptible(reason = CALLED_FROM_UNINTERRUPTIBLE_CODE, mayBeInlined = true)
    protected void install0(IsolateThread thread) {
        /* The timer is global, so nothing to do here. */
    }

    @Override
    @Uninterruptible(reason = CALLED_FROM_UNINTERRUPTIBLE_CODE, mayBeInlined = true)
    protected void uninstall0(IsolateThread thread) {
        /* The timer is global, so nothing to do here. */
    }
}
